The effect of glass transition on gas permeabilities

Abstract

Abstract Gas permeabilities of a copolymer of acrylonitrile and methyl acrylate were examined at the temperature range of 25° to 80°C. The change of activation energy of gas permeability constant at the glass transition temperature (65°C) was observed with N 2 , Ar, O 2 , and CO 2 , but no change was observed with He. The observation of the change of slope of the Arrhenius plot of gas permeability is discussed as a function of the diffusion constant ( D ) of a permeant gas at the glass transition temperature ( T g ). The change occurs only if the value of D at T g is smaller than a certain value (i.e., 5 × 10 −8 ), according to the analysis of data appearing in the literature.